Slave rice cultivators commonly worked by the which involved a specific assignment for a day's work.

Slave rice cultivators commonly worked by the TASK SYSTEM, which involved a specific assignment for a days work. :)

The correct answer is ''Task System''.

Explanation:

To begin with, task system is the name given to the term that refers to a model or system of labor under slavery that was very common in the Americas and whose main characteristics were that the slaves work every day with a different specific task and after that task was done the slave could do what he wanted with the time ramaining. Furthermore, this form was not so brutal in comparison with other forms of slavery. In addition, this type of labor system was very popular among the slave rice cultivators in the American colonies.